Hydraulic governors



Oct. 5, 1965 J- c. POTTER 3,209,613

HYDRAULIC GOVERNORS Filed Sept. 17, 1962 FIG.2 T

United States Patent 3,209,613 HYDRAULIC GOVERNORS James Charles Potter,Chiswick, London, England, assignor to C.A.V. Limited, London, EnglandFiled Sept. 17, 1962, Ser. No. 223,875 Claims priority, applicationGreat Britain, Sept. 21, 1961, 33,7 98/ 61 2 Claims. (Cl. 74472) Thisinvention relates toa hydraulic governor for controlling the rate ofsupply of liquid fuel to an internal combustion engine in response tovariations in the speed of the engine, the governor being of the kindwherein a pump adapted to be driven by the engine is arranged to deliverfuel through a circulatory system, and wherein the pressure differenceacross an orifice or orifices in the system is caused to control thesetting of means for regulating the supply of fuel to the engine.

In vehicles incorporating internal combustion engines adapted to drivethe vehicle wheels through a variable speed gear, it is often requiredthat the speed of the engine should be prevented from rising above apredetermined value whilst driving the wheels through relatively highgear ratios such, for example, as when direct top gear, and/or overdrivetop gear is engaged, but when lower ratios are engaged, the engineshould be capable of operating at a speed above the predetermined valueto provide high torques for large loads.

1 The object of this invention is to enable this requirement to be metin a convenient manner with a governor of the kind specified.

According to the invention a hydraulic governor of the kind specifiedincorporates, in parallel with said orilice or orifices, a furtherorifice, and valve means for preventing fluid flow through said furtherorifice when a selected gear ratio, or selected gear ratios, areengaged.

In the accompanying drawings:

FIGURE 1 is a sectional view of one example of the invention and FIGURE2 is a diagrammatic view showing how part of the example shown in FIGURE1 can be operated.

FIGURE 3 is a diagrammatic plan view of the essential components of amotor vehicle to which the example is applied.

Referring to the drawings, there is provided a body part 1 having formedtherein a plurality of passages 2, 3, 4 and 5 these passages formingparts of a circulatory system through which liquid can flow under theaction of a gear pump 6 adapted to be driven by the internal combustionengine. In the system is formed a cylindrical chamber 7 whichcommunicates at one end with the passage 3 and at the other end with thepassage 4. The chamber 7 contains a regulating piston 8 which is loadedby a spring 9, and from which extends a rod 10 having its outer endconnnected to a lever 11, the latter being adapted to actuate the usualregulating means of the injection pump which supplies liquid fuel to theengine. Also between the circulating pump 6 and the chamber 7 is formeda second cylindrical chamber 12 which at one end is connected by thepassage 2 to the delivery side of the pump 6, and at the other end isconnected by the passage 3 to the corresponding end of the first chamber7. The second chamber 12 contains a hollow piston 13 having in its endan orifice or orifices 14 through which the liquid from the circulatingpump 6 can flow with an appropriate pressure drop which is a function ofspeed, and on the end of this piston rests the stem 15 of a controlvalve 16 which serves by cooperation with a seating at one side of aport 17 to control communication between the passages 3, 4 and thus tocontrol the flow of liquid in the system. The valve 16 is loaded by aspring 18 which is contained within a hollow extension of the valve andthe interior of another and coaxial hollow valve 19 which serves as aguide for the first valve, and which controls a by-pass between thepassage 4 and the passage 5, the latter passage being in communicationwith the suction side of the pump 6. The by-pass above mentioned isformed in part by a passage 20 in which the by-pass valve 19 is slidablysupported by longitudinal ribs 21 on this valve and in part by a chamber22 between the last mentitoned passage and the passage 5. The by-passvalve 19 co-operates with a slotted skirt 23 at one end of the by-passpassage 20 to control communication between this passage and the passage4, and this is loaded by the same spring 18 as the first valve 16, thisspring tending to move the by-pass valve to its closed position. valve19 against the action of the spring 18 is effected by a cam-like lever24 mounted in the by-pass chamber 22, this lever being adapted to act onthe adjacent end of the by-pass valve, and being operable by a lever 25which is controlled by the driver. Also in parallel with the by pass 20,22 is arranged a variable choke consisting of a piston valve 26 which isslidable in a ported sleeve 27, and is loaded by a spring 28, the outerend of the valve being in contact with an adjustable abutment 29 on theabove mentioned lever 11 which transmits movement to the regulting meansof the fuel pump. The variable choke serves to control communicationbetween the passages 4, 5.

The operation of the governor will now be described. When it is requiredto start the engine the lever 24 is set in a position such that theby-pass valve 19 is closed, the engine is then cranked and thecirculating pump 6 causes liquid under pressure to pass through theorifice 14 of the hollow. piston 13 to one side of the regulating piston8 and to move the latter, in opposition to its spring 9, to cause thefuel pump regulating means to be so actuated as to enable the maximumamount of fuel to be delivered by the pump. When the engine begins torotate under its own power, the pressure acting on the underside of thepiston 13 increases sufficiently to open the valve 16, thereby allowingliquid to pass to the other side of the regulating piston 8 and returnto the suction side of the pump 6 through the variable choke 26, 27. Theconsequent rise of pressure on that side of the regulating piston 8assists the spring 9 to return the regulating piston to a new positionof equilibrium, in which the rate of supply of fuel from the fuel pumpis reduced to an amount corresponding to the idling requirements of theengine. The movement of the regulating piston 8 is simultaneouslytransmitted to the piston valve 26 of the variable choke to produce anincreased opening thereof, and this action tends to oppose the change inposition of the regulating piston. To obtain an increase of the speed ofthe engine, the cam like lever 24 is actuated by the driver so as toopen the by-pass valve 19 and increase the spring pressure on the firstvalve 16, the amount of movement given to the cam like lever beingdependent on the fuel requirements of the engine. This action causes theliquid pressure on the side of the regulating piston 8 remote from thespring 9 to be increased and that on the other side to be decreased,with consequent increase of the fuel pump delivery. When the speed ofthe engine has increased sufficiently to produce a pressure drop throughthe orifice or orifices 14 of the hollow piston 13 such as to cause thelatter to open the control valve 16, the pressure in the system willdrop sufficiently to allow the spring 9 to move the regulating piston 10into a new position of equilibrium.

In carrying the present invention into effect there is provided inparallel with the orifice or orifices 14 a further orifice 30 which isformed in a passage 31. Also incorporated in the passage 31 is a valve32 which is spring loaded towards a closed position and which isarranged Movement of the by-pass" to be opened when an electro-magnet 33is energised. The electro-magnet is arranged to be energised under thecontrol of a switch 34 operable by the gear shift lever 37 of thevehicle the lever being movable within a selector gate 36, and theswitch being closed when selected gear ratios, such, for example as allgear ratios below the highest gear ratio are engaged. The selector gate36 and gear shift lever 37 are associated with a multi-ratio gearbox 38disposed intermediate an engine 39 and the drive axle unit 40, thelatter carrying a pair of driven road engaging wheels 41 of the vehicle.

Conveniently the further orifice 30 is adjustable so that discrepanciesbetween individual governors can be accommodated and it may comprise anaxially adjustable rod 35 movable in a direction substantially at rightangles to the fluid flow in the passage, the end of the rod froms thefurther orifice with the wall of the passage 31.

In use, therefore, when the highest gear is engaged, the hydraulicgovernor operates as described above. However, when a lower gear ratiois engaged the valve is opened to permit flow through the furtherorifice from the passage 2 to the passage 3. As a result the pressurediflerence across the piston 13 is less for any given engine speed, andconsequently the maximum engine speed for any given setting of the leveris increased. Moreover, since the valve 32 is opened when theelectro-magnet is energised, in the event of an electric failure, themaximum engine speed for a given setting of the lever 24 is restrictedto the lower value on all gear ratios.

Having thus described my invention what I claim as new and desire tosecure by Letters Patent is:

1. A hydraulic governor for controlling the rate of supply of liquidfuel to a vehicle internal combustion engine of the kind having amulti-ratio gearbox associated therewith, the governor comprising a bodypart, a fluid pump mounted within said body part and adapted to bedriven by the engine, a fluid outlet from the pump, a passage in thebody part connected to said outlet, an orifice positioned in saidpassage and across which a pressure dilference will be developed whenfluid passes through the passage, means movable in response to thepressure downstream of said orifice, the position of said means servingto determine the rate of supply of liquid fuel to the engine, a furtherpassage in the body part, said further passage being connnected inparallel with said orifice, a further orifice positioned in said furtherpassage and which when fluid is delivered by the pump modifies thepressure to which the means is subjected, and valve means mounted insaid further passage, said valve means being operable to prevent theflow of fluid through said further orifice when a selected ratio of thegearbox is engaged.

2. A hydraulic governor for controlling the rate of supply of liquidfuel to a vehicle internal combustion engine of the kind having amulti-ratio gearbox associated therewith, the governor comprising a bodypart, a fluid pump mounted within said body part and adapted to bedriven by the engine, a fluid outlet from the pump, a passage in thebody part connected to said outlet, an orifice positioned in saidpassage and across which a pressure difference Will be developed whenfluid passes through the passage, means movable in response to thepressure downstream of said orifice, the position of said means servingto determine the rate of supply of liquid fuel to the engine, a furtherpassage in the body part, said further passage being connected inparallel with said orifice, a further orifice positioned in said furtherpassage and which when fluid is delivered by the pump modifies thepressure to which the means is subjected, a valve seating in saidfurther passage, a valve closure member for co-operation with saidseating, resilient means for urging the valve closure member intocontact with the valve seating to prevent the flow of fluid through saidfurther passage, a solenoid mounted within the body part, a solenoidarmature connected to the valve closure member and which when thesolenoid is energized moves the closure member to permit fluid flowthrough said further passage, said solenoid being de-energised when aselected ratio of the gearbox is engaged.

References Cited by the Examiner UNITED STATES PATENTS 9/41 Kendrick91-31 10/59 Nallinger 74472.1

1. A HYDRAULIC GOVERNOR FOR CONTROLLING THE RATE OF SUPPLY OF LIQUIDFUEL TO A VEHICLE INTERNAL COMBUSTION ENGINE OF THE KIND HAVING AMULTI-RATIO GEARBOX ASSOCIATED THEREWITH, THE GOVERNOR COMPRISING A BODYPART, A FLUID PUMP MOUNTED WITHIN SAID BODY PART AND ADAPTED TO BEDRIVEN BY THE ENGINE, A FLUID OUTLET FROM THE PUMP, A PASSAGE IN THEBODY PART CONNECTED TO SAID OUTLET, AN ORIFICE POSITIONED IN SAIDPASSAGE AND ACROSS WHICH A PRESSURE DIFFERENCE WILL BE DEVELOPED WHENFLUID PASSES THROUGH THE PASSAGEWAY, MEANS MOVABLE IN RESPONSE TO THEPRESSURE DOWNSTREA, OF SAID ORIFICE, THE POSITION OF SAID MEANS SERVINGTO DETERMINE THE RATE OF SUPPLY OF LIQUID FUEL TO THE ENGINE, A FURTHERPASSAGE IN THE BODY PART, SAID FURTHER PASSAGE BEING CONNECTED INPARALLEL WITH SAID ORIFICE, A FURTHER ORIFICE POSITIONED IN SAID FURTHERPASSAGE AND WHICH WHEN FLUID IS DELIVERED BY THE PUMP MODIFIES THEPRESSURE TO WHICH THE MEANS IS SUBJECTED, AND VALVE MEANS MOUNTED INSAID FURTHER PASSAGE, SAID VALVE MEANS BEING OPERABLE TO PREVENT THEFLOW OF FLUID THROUGH SAID FURTHER ORIFICE WHEN A SELECTED RATIO OF THEGEARBOX IS ENGAGED.